Please bear with me if my question looks long. I always ask very short questions, but this is to help my son with his exam preparation.
This is the question on change of narration in one book :

When they had assembled in front of him , he said ," When I asked you yesterday if you were happy with your lives, all of you said you were contented and did not need anything more. Yet, today I can see the sadness in your faces when you had to leave behind the riches you had gathered in my garden. If you were really happy with your lives, why did you gather the jewel fruits, and why are you so sad now? "

The answer given in the book is :
When they had assembled in front of him he said that when he asked them the previous day whether they were happy with their lives, all of them had said that they were contented and needed nothing more. He added that yet he could see that day the sadness in their faces when they had to leave behind the riches they had gathered in his garden. He further asked that if they were really happy with their lived why they had gathered the jewel fruits and why were so sad that then.

I have few doubts about this answer :

1)For 'I asked you' : It should be he had asked them ... in place of he asked them.

2) for ' if you were happy ' : It should be whether they had been happy - in place of whether they were happy.

3) For ' you were contented ' : It should be they had been contented - in place of they were contented.

4) For ' if you were really happy ... ' : It should be whether they had been really happy - in place of whether they were really happy.
Please share your view and bear with me if it is a long post.